The present invention concerns a multiple complex shear ddevice which operates in two stages to split metallic bars or billets which are continuously extruded from a casting mill, into smaller bars or billets of rectangular or square cross section.
More particularly, the present invention is concerned with a dual mechanical complex shear. The first shearing complex is in the form of a circular shear, which partially cuts (about 2/3) a hot metallic bar and partially displaces it along the cutting line to generate shearing stresses in the hot metallic bar as it exits from the extrusion or casting mill of a steel plant. The second shearing complex both wedges and shapes the displaced portions of the metallic bar into separate and properly formed smaller bars along the shearing stresses.
The present invention is intended to provide a means by which a single casting mill specializing in forming larger bars, can be used to provide differently and variously sized smaller steel bars, as required. This feature provides for a tremendous savings in capital investments, as well as in running and operating costs, over the various prior methods and aparatuses for obtaining different sized bars.
One prior method requires the use of a different mill for each differently sized form required. Unless one can find a customer for the continuous output of such a mill, this solution requires equipment which is not fully utilized. Unless plants are run at optimum levels, they cannot be most efficiently used because a ready market for full product output of any particular size casting does not always exist.
At present, mechanized means are not believed to exist for the efficient longitudinal shearing of larger bars into smaller bars, and which mechanized means can be used in series continuously with the output of an extrusion or casting mill. Occasionally, a longitudinal shear has been used to split larger bars into smaller bars, but this has not been accomplished in line with the casting or extrusion mill. In addition, this has only been done in a limited way due to excessive swarf information and the very high cost involved in shearing and trimming the bars.
As noted above, steel plants presently produce metallic bars using a continuous casting method and are generally divided into plants producing large, normal, and small cross-sectioned products, as required by the customers of the extrusions. Each of these plants must necessarily have a number of lines to produce castings or extrusions as required. As can readily be realized, by using a shear device to split a single casting or extrusion into a number of smaller sizes, as required, a number of economies can be realized. In addition, plants presently specializing in large bars can now produce smaller rectangular sections such as blooms or billets or semi-finished products. In general, this means that one can produce a single large casting having one dimension which is of the desired size and another dimension which is a multiple of the second desired dimension. The single casting can then be sheared and shaped into a multiple of smaller castings of the desired size.
The present invention also has utility for use in blooming plants or mills wherein ingots of metal, for example ingots produced at other steel plants, are rolled into finished form. At present, it is necessary to roll the ingot successively until the desired shape is formed. Such mills can be very complicated and are very expensive to build and to operate. Often, the results are inadequate or obtained only with low efficiency and, therefore excessive cost. The shearing stress produced by blooming mills is limited and often results in an increase in the amount of swarf (or waste trimmings) that result. Sometimes, it is necessary to reheat the bars back to the temperature at which they were originally rolled using furnaces which are expensive to build and to operate. Using a shear device according to the present invention, and locating it in the rolling mill line, it will again only be necessary to roll the ingot to produce a section of a thickness equal to the height of the section to be formed and a width equal to the sum of the widths of all the bars to be formed by use of the shearing device according to the present invention. The rolled ingot can then be sheared into the appropriately sized bars.
Consequently, the introduction of a shear device, according to the present invention, into plants for the production of steel bars, either by continuous casting or extrusion, or by the rolling of ingots or the like, can be used to avoid many of the disadvantages of the prior methods, while reducing production costs and increasing the flexibility of a particular processing line.
It is therefor an object of the present invention to provide a shear device which continuously shears a hot metal bar in a longitudinal direction of the hot metal bar to form therefrom smaller metal bars having a square or rectangular cross-section.
It is a further object of the invention to provide a shear device which operates continuously on a continuously cast or extruded steel bar as it comes from the steel mill or out of a blooming mill.
Another object of the invention is to provide a shear device which operates in two stages to produce a plurality of metallic bars from a single larger bar, in which the smaller bars are trimmed and have been produced with a minimum of swarf or waste.